1. Field of the Invention:
The present invention relates, in general, to a loop transport system for baskets containing looped rod material to be drawn through a drawing machine and, more particularly, this invention relates to a transport system laid out in a substantially endless loop to which a predetermined plurality of baskets containing such looped rod material to be drawn can be fed in sequence to each of a feeder station, a payoff station, a delivery station and a basket removal station in a manner such that the functions performed in each of the individual stations can be conducted in a staggered and/or at least a partially simultaneous fashion. The present invention, also, encompasses a method of minimizing lost production in a substantially closed loop transport system of the type described above.
2. Description of the Prior Art:
Prior to the present invention a number of transport systems for baskets containing looped rod material to be drawn have been taught in the prior art. Further a number of these systems are in commercial use in industry. Generally these transport systems for such baskets containing the material to be drawn are components of the drawing block units. In order to provide economy of operation in drawing of rods, it is common practice to provide a plurality of baskets and basket stations for the execution of the work sequence. It is necessary, generally in chronological order, to first introduce a basket into the loop system. After such basket has been introduced into the loop system, one end of the looped rod material is prepared for a pointing operation. The prepared end of the looped rod material is then pointed and the basket is sent to a payoff station positioned ahead of the drawing die. The looped rod material is fed through the drawing unit and discharged into a basket positioned at a delivery station beneath the drawing block. Thereafter the basket containing the finished drawn looped rod material is either fed to a second drawing process for a further reduction in cross-sectioned size or the basket may be removed from the transport loop system.
It has been found, through experience of operation, that the economical utilization of the drawing machine equipment becomes possible only when the above-mentioned functions performed in each of the individual stations can be performed at least in a partially simultaneous manner. It has also been found that the upper limit for the number of stations as well as the number of baskets containing the looped rod material to be drawn ranges between seven to nine.
In one prior art transport system arrangement, a so-called forced loop system is used. In such a forced loop system, all of the baskets pass through the various stations provided in a loop by means of cars. Such cars are connected to one another by chains, cables, etc.
The prior art also includes unconnected loop system arrangements. In such unconnected loop systems, all of the baskets containing the looped rod material to be drawn pass through each of the various stations individually. For example, they are transported on a roller train or conveyor. Regardless of which transport system is used, depending on the final sizes to be produced in the drawing operation, all of the baskets containing the looped rod material to be drawn in such loop transport system will pass through each of the individual stations at least once and possibly a plurality of times.
Furthermore, in spite of how carefully the drawing program is laid out, with respect to the reduction of the number of individual trains required, a problem persists when the looped rod material being drawn becomes torn apart repeatedly. When a tear in the looped rod material occurs, after a portion of a coil has already been proceeded through the die member of the drawing apparatus and has been discharged into the delivery basket positioned beneath the drawing block, the conventional prior art practice is to shut the system down. After the system has been shut down the basket containing the remaining portion of the looped rod material is run back to the pointing station to have a point prepared on the end of the remaining looped rod material. Thereafter, the system is switched to forward so that the remainder of the looped rod material can be drawn and deposited in the basket containing the other portion of such drawn looped rod material.
The delay encountered by such a tear in the looped rod material continues during the subsequent drawings, down to the final product size, and can significantly lengthen the overall drawing time. Clearly, there is an increased cost associated with the drawing as well.